Hi, my backup comp that I had in an old Antec Sonata 2 case and swapped it to a NZXT case, I have a Asus P5N32-E SLI, with a E6600 chip running everything stock with CPU watercooled using NCIX's watercooling bundle for $120.
Other then lack of airflow to rid of mobo ambient temps in my old case, everything worked fine, I got a 90mm fan to help keep things cool aswell as a Antec 3 speed 80mm spot fan, and everything worked fine.
After swapping to the new case with everything the same, it wont boot past post, and when it does it locks up in BIOS or during windows startup if it gets to that point.
My temps are reading, CPU 30 on idle/boot, system board running roughly 40-45....
I was using a 8800GTS card before swapping cases, I sent my 8800GTS in for stepup before swapping cases, I am now using a 7600GT but have swapped with dif cards and still locks up in BIOS and wont boot.
I haven't tried draining and refilling my watercooling setup yet, but dont see why that would be the problem since my temps seem fine, when I can get into bios.
I have reset the CMOS, I have done a PSU self test and its working fine, I have tried dif HDD's, and GFX cards.... the only thing I haven't tried to swap was my sys board.
Does anyone have any suggestions as to what it could be?
Here is my system specs...
E6600 CPU
Asus P5N32-E SLI
Silverstone Strider 750w Modular
Mushkin SP2 6400 2Gb Ram
Seagate Barracuda 250Gb 7200RPM
Also running 2 SATA optical drives.
And I now have water leakage! SHIT
Well if anyone can help I will try and find the leak in the meantime!

It wasn't leaking before I started troubleshooting, but during attemting to figure out WTF is going on, But that hasn't been an effect on the issue.... other then when I was trying to figure it out... plz let me know ASAP!

If everything is sitting at stock speeds my first guess would be memory settings. You can try booting into bios with only one stick of mem and loosening timings.

Other than that.... those system temps sound pretty high (I'm assuming you're talking deg C.) you could try leaving the case side off and directing the airflow from a house fan at the mobo to see if that solves the problem... if it does, then you could try reseating your heatsinks and re-applying some new tim for them.